Polarization Reversal in MgO:LiNbO3 Single Crystals Modified by Plasma-Source Ion Irradiation

The polarization reversal has been studied by domain structure visualization and switching current recording in LiNbO3 single crystals doped by 5% MgO irradiated by Ar+ ions. The abnormal domain structure evolution representing formation of charged domain walls has been revealed. It has been shown that low energy ion irradiation leads to increase of the bulk conductivity due to oxygen out-diffusion induced by radiative heating in vacuum. The inhomogeneous distribution of the electric field terminated the polarization reversal in high conductive layer. The analysis of the switching current data allowed revealing the input of the conductive current through charged domain walls.